Schematic view of the Pipe nebula cloud, Ophiuchus streamers and Sco OB2 association. The solid straight lines represent the streamers and main body of the Ophiuchus and Pipe molecular clouds, respectively. The plus symbol marks the central position of the Sco OB 2 association. The star symbols represent the positions of some of the main members of the association, and the HI bubble observed by de Geus (1992) is also indicated.